In his 2008 memoir, “Don’t Sleep, There Are Snakes,” the linguist Dan Everett recalled the night members of the Pirahã — the isolated Amazonian hunter-gatherers he first visited as a Christian missionary in the late 1970s — tried to kill him.

Dr. Everett survived, and his life among the Pirahã, a group of several hundred living in northwest Brazil, went on mostly peacefully as he established himself as a leading scholarly authority on the group and one of a handful of outsiders to master their difficult language.

His lifeamong his fellow linguists, however, has been far less idyllic, and debate about his scholarship is poised to boil over anew, thanks to his ambitious new book, “Language: The Cultural Tool,” and a forthcoming television documentary that presents an admiring view of his research among the Pirahã along with a darkly conspiratorial view of some of his critics.

Members of the Pirahã people of Amazonian Brazil, who have an unusual language, as seen in “The Grammar of Happiness.” Essential Media & Entertainment/Smithsonian Channel

In 2005 Dr. Everett shot to international prominence with a paper claiming that he had identified some peculiar features of the Pirahã language that challenged Noam Chomsky’s influential theory, first proposed in the 1950s, that human language is governed by “universal grammar,” a genetically determined capacity that imposes the same fundamental shape on all the world’s tongues.

The paper, published in the journal Current Anthropology, turned him into something of a popular hero but a professional lightning rod, embraced in the press as a giant killer who had felled the mighty Chomsky but denounced by some fellow linguists as a fraud, an attention seeker or worse, promoting dubious ideas about a powerless indigenous group while refusing to release his data to skeptics.

The controversy has been simmering in journals and at conferences ever since, fed by a slow trickle of findings by researchers who have followed Dr. Everett’s path down to the Amazon. In a telephone interview Dr. Everett, 60, who is the dean of arts and sciences at Bentley University in Waltham, Mass., insisted that he’s not trying to pick a fresh fight, let alone present himself as a rival to the man he calls “the smartest person I’ve ever met.”

“I’m a small fish in the sea,” he said, adding, “I do not put myself at Chomsky’s level.”

Dan Everett in the Amazon region of Brazil with the Pirahã in 1981. Courtesy Daniel Everett

Still, he doesn’t shy from making big claims for “Language: The Cultural Tool,” published last week by Pantheon. “I am going beyond my work with Pirahã and systematically dismantling the evidence in favor of a language instinct,” he said. “I suspect it will be extremely controversial.”

Even some of Dr. Everett’s admirers fault him for representing himself as a lonely voice of truth against an all-powerful Chomskian orthodoxy bent on stopping his ideas dead. It’s certainly the view advanced in the documentary, “The Grammar of Happiness,” which accuses unnamed linguists of improperly influencing the Brazilian government to deny his request to return to Pirahã territory, either with the film crew or with a research team from M.I.T., led by Ted Gibson, a professor of cognitive science. (It’s scheduled to run on the Smithsonian Channel in May.)

A Pirahã man in the film “The Grammar of Happiness.” Essential Media & Entertainment/Smithsonian Channel

Dr. Everett acknowledged that he had no firsthand evidence of any intrigues against him. But Miguel Oliveira, an associate professor of linguistics at the Federal University of Alagoas and the M.I.T. expedition’s Brazilian sponsor, said in an interview that Dr. Everett is widely resented among scholars in Brazil for his missionary past, anti-Chomskian stance and ability to attract research money.

“This is politics, everybody knows that,” Dr. Oliveira said. “One of the arguments is that he’s stealing something from the indigenous people to become famous. It’s not said. But that’s the way they think.”

Claims of skullduggery certainly add juice to a debate that, to nonlinguists, can seem arcane. In a sense what Dr. Everett has taken from the Pirahã isn’t gold or rare medicinal plants but recursion, a property of language that allows speakers to embed phrases within phrases — for example, “The professor said Everett said Chomsky is wrong” — infinitely.

In a much-cited 2002 paper Professor Chomsky, an emeritus professor of linguistics at M.I.T., writing with Marc D. Hauser and W. Tecumseh Fitch, declared recursion to be the crucial feature of universal grammar and the only thing separating human language from its evolutionary forerunners. But Dr. Everett, who had been publishing quietly on the Pirahã for two decades, announced in his 2005 paper that their language lacked recursion, along with color terms, number terms, and other common properties of language. The Pirahã, Dr. Everett wrote, showed these linguistic gaps not because they were simple-minded, but because their culture — which emphasized concrete matters in the here and now and also lacked creation myths and traditions of art making — did not require it.

To Dr. Everett, Pirahã was a clear case of culture shaping grammar — an impossibility according to the theory of universal grammar. But to some of his critics the paper was really just a case of Dr. Everett — who said he began questioning his own Chomskian ideas in the early 1990s, around the time he began questioning his faith — fixing the facts around his new theories.

In 2009 the linguists Andrew Nevins, Cilene Rodrigues and David Pesetsky, three of the fiercest early critics of Dr. Everett’s paper, published their own in the journal Language, disputing his linguistic claims and expressing “discomfort” with his overall account of the Pirahã’s simple culture. Their main source was Dr. Everett himself, whose 1982 doctoral dissertation, they argued, showed clear evidence of recursion in Pirahã.

“He was right the first time,” Dr. Pesetsky, an M.I.T. professor, said in an interview. “The first time he had reasons. The second time he had no reasons.”

Some scholars say the debate remains stymied by a lack of fresh, independently gathered data. Three different research teams, including one led by Dr. Gibson that traveled to the Pirahã in 2007, have published papers supporting Dr. Everett’s claim that there are no numbers in the Pirahã language. But efforts to go recursion hunting in the jungle — using techniques that range from eliciting sentences to having the Pirahã play specially designed video games — have so far yielded no published results.

Still, some have tried to figure out ways to press ahead, even without direct access to the Pirahã. After Dr. Gibson’s team was denied permission to return to Brazil in 2010, its members devised a method that minimized reliance on Dr. Everett’s data by analyzing instead a corpus of 1,000 sentences from Pirahã stories transcribed by another missionary in the region.

Their analysis, presented at the Linguistic Society of America’s annual meeting in January, found no embedded clauses but did uncover “suggestive evidence” of recursion in a more obscure grammatical corner. It’s a result that is hardly satisfying to Dr. Everett, who questions it. But his critics, oddly, seem no more pleased.

Dr. Pesetsky, who heard the presentation, dismissed the whole effort as biased from the start by its reliance on Dr. Everett’s grammatical classifications and basic assumptions. “They were taking for granted the correctness of the hypothesis they were trying to disconfirm,” he said.

But to Dr. Gibson, who said he does not find Dr. Everett’s cultural theory of language persuasive, such responses reflect the gap between theoretical linguists and data-driven cognitive scientists, not to mention the strangely calcified state of the recursion debate.

“Chomskians and non-Chomskians are weirdly illogical at times,” he said. “It’s like they just don’t want to have a cogent argument. They just want to contradict what the other guy is saying.”

Dr. Everett’s critics fault him for failing to release his field data, even seven years after the controversy erupted. He countered that he is currently working to translate his decades’ worth of material and hopes to post some transcriptions online “over the next several months.” The bigger outrage, he insisted, is what he characterized as other scholars’ efforts to accuse him of “racist research” and interfere with his access to the Pirahã.

Dr. Rodrigues, a professor of linguistics at the Pontifical Catholic University in Rio de Janeiro, acknowledged by e-mail that in 2007 she wrote a letter to Funai, the Brazilian government agency in charge of indigenous affairs, detailing her objections to Dr. Everett’s linguistic research and to his broader description of Pirahã culture.

She declined to elaborate on the contents of the letter, which she said was written at Funai’s request and did not recommend any particular course of action. But asked about her overall opinion of Dr. Everett’s research, she said, “It does not meet the standards of scientific evidence in our field.”

Whatever the reasons for Dr. Everett’s being denied access, he’s enlisting the help of the Pirahã themselves, who are shown at the end of “The Grammar of Happiness” recording an emotional plea to the Brazilian government.